Despite a fair amount of college physics and math, and the insights that come from being a living conscious being on planet earth which you’d think would give some insight into the nature of the reality we experience on a daily basis all around us, I remain confused.
How can the *physical universe* have no center? Almost all theories of cosmology and all of the extensive and available data is said to support this idea, but it still completely baffles me. Earth has a center, the Galaxy has a center, and our Galactic Cluster has a center. But at cosmic universe scales you cannot talk about “centers” anymore – ie the point where the big bang happened. My understanding is there is no point of origin – almost all cosmologies that are consistent with the (huge amount) of physical data say the universe sprung into being but did NOT spring from any particular spot.
Now, one way this *does* make sense to me is to assume that the basis of reality is tiny bits of information rather than tiny bits of matter and energy. ie matter and energy are a great way to model things down to a certain level, but at the very heart of everything we’ve just got some sort of binary information thing – zero or one, yes or no, on or off, “something or nothing”, etc.
This is appealing at one level because it seems to simplify some of the ultimate questions to about the simplest dynamic concept you can imagine which allows only two conditions – ie something or nothing. A concept that allows only ONE condition would be totally static – I don’t see how you could have change or thought in a system that is defined with only a single contruct, but clearly if you add only one more condition, giving you the “on or off” 1 or 0, etc, you can get an infinite number of variations.
Yes on the information thingie, there, but it’s kind of a moot point b/c information is so very closely tied to spacetime that there’s no essential difference that I can see. “Time Is,” to all us grasshoppers.
Think of the inflationary universe as the surface of a balloon — as I recall that’s how my physics prof. ‘splained it to me. Don’t tell me balloons got centers, neither, ‘cuz we can’t play in that dimension.
Tommo the thing that bugs me about the balloon analogy is that we’ve got the intuitive 3D reference stuff going just fine out to the galactic cluster level, so when and why do the 3D reference points “end” ?
e.g. you can theoretically fly a ship from here to there and then from earth to the center of the Milky way and from the milky way to Andromeda Galaxy, all using pretty normal “take a left turn at Sirius” kind of directions.
Why and where do those instructions break down and what do you see out of the window when that happens?
Hey Tommo “Time Is” ?
Was that the movie we used to run (often backwards) at Campus school along with Donald Duck in MatheMagic Land and those nasty WWII atrocity films?
Those were the days.
Einstein I am not, but given the finite speed of light (and stable constants), everything known (at least observational data) about very distant objects–the Andromeda galaxy is what 2.5 million light years away–or the edge of the universe occurred a few million years ago. Many astronomy (or pop-astronomy) buffs seem to forget that. A rather long haul to Andromeda, even at speed of light.
Any plausible interstellar adventures will have to wait until NASA (if it even exists apres-Obama) builds crafts far more powerful than what they currently have. That said, some modest scale space projects–say internet cafes in orbit (to Cafe Orbital, dude!)—should be encouraged.
Horatiox my understanding is that the Hubble and Chandra “deep field” shots are actually observations of the state of distant galaxies some 10+ *billion* years ago. So science is basing the cosmologies on real observations. The images we see are literally from 0 to billions of years old depending on the distance of the galaxy we are seeing.
“Time Is” — the very same. I remember the Donald Duck movie, and on a topical note I cast my very first Presidential ballot for dear old Donald. In retrospect that may not have been the wisest choice.
I don’t recall the atrocity films, but have a strong and somewhat random memory of the old Autocrapper line from the USMC map reading course, “You have been captured [due to your lousy map-reading skills] and will be mercilessly tortured.” I say this when my wife and I are driving and there is a possibility we may be lost. She upholds her end of the script and tortures me for saying it, although she is not without mercy…
Oh, and on the balloon thing — the Earth seems flat, don’t it? Changing the scale alters perspective.
“””So science is basing the cosmologies on real observations.””””
A key point, however mundane. “Normal science”, whether astronomy or bio-chemistry, depends on observation (whether via telescope or microscope) and falsifiability, on testable hypotheses. Some of the new physics tends to be abnormal science, if not mysticism of some type (i.e. string theory, multiverse theory, etc.), and there are physicists and academic scientists who have objected to the lack of observable data. I’m a bit of a functionalist when it comes to Big Science: if experiment/research X doesn’t work, or solve important problems, or function and/or compute in the real world, it doesn’t mean anything. High def. pics of the Horsehead Nebula are quite cool, but are they worth the billions it took to get ’em? Not sure.
“It is impossible to travel faster than the speed of light, and certainly not desirable, as one’s hat keeps blowing off” — Woody Allen
Ha – thx for checking in lvs
Horatiox good caveats, esp. falsifiability which seems to have dropped by the wayside as things like string theory and climate models have become very hot new topics in the mainstream science community.
I’d even go so far as to suggest this is in part due to the fallout from the sensibilities that drove many in the 1960s – mostly a tendency for “appealing” and “mystical” ideas to be held to a lower standard of proof.
I wonder if someone could build a space telescope big and powerful enough that it could see all the way across the universe and capture an image of the backside of the telescope. Of course we would have to wait an unimaginably long time for the light from the backside of the telescope to reach the front of it. Or maybe that’s not how physics works. However the scenario would run, I think I just blew my mind. o.O
I didn’t personally know that our physical universe don’t have a center. I studied college and graduated in electronics but I never really thought about it until reading it from here.
Another thing.. how could our physical universe have sprung from what it is today when it doesn’t even have a point of origin? Doeesn’t make sense to me at all.
One of you asked:
> I wonder if someone could build a space telescope that could see all the way across the universe and capture an image of the backside of the telescope.
A very reasonable question! As someone with a degree in astronomy (and a special interest in relativity), I would be happy to answer it for you.
==[ THE SHORTEST ANSWER is a pseudometric topological equation, which DOES explain it, but is such a compressed way of saying it that I’ll omit that one.
===[ A SHORT ANSWER which may be difficult because it’s still somewhat compressed:
The universe is not just a 3D object, like a chair (or a galaxy). The universe has FOUR dimensions. The shape of the universe is “hyperbolic”, meaning that it “wraps around”. The balloon analogy is EXACTLY what’s happening, but while the 2D balloon wraps around in 3D space, the 3D universe wraps around in 4D space (called “hyperspace”, but don’t get scared of the name. it’s reeeeally simple!)
An ant on an expanding balloon COULD leave his house, walk in one direction, and end up at his back door. So why can’t we see the backside of the telescope (or our galaxy)? Well, think of the ant. She has to walk faster than the balloon is expanding, which in 3D space, means going faster than light (which is impossible). Explaining why you have to go faster than light to cross the entire universe would require a longer (but still simple) answer.
===[ A MORE UNDERSTANDABLE ANSWER but longer:
Go to my blog index (URL at end), then scroll down to the section “Knowledge Is Not Power – geek stuff”. Warning: IGNORE THE SILLY STUFF ABOVE THAT. In particular, don’t be distracted by the naked pictures of me.
To no one in particular, I explain stuff like:
— “well where IS this fourth spatial dimension then, Faye?” (The answer is that the fourth dimension is TIME.)
— “So if time is a spatial dimension, like the other three, then can it be measured in feet instead of seconds?”
Answer: yes, absolutely, and it’s easy! (In fact, I figured it out myself one Saturday afternoon when I was in 6th grade!) Just multiply the seconds by the speed of light and you get an answer in feet. (For example, one nanosecond is almost exactly one foot long.) The reason this is true is obvious once it’s explained to you– also easy to do)
— “If time is a spatial dimension like the other three, why can’t I point a yardstick in that direction?”
The answer to that one (and others) will REALLY freq you out!!
===[ faye kane, homeless brain
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